Shock-absorber.



A. W. BLANCHARD.

SHOCK ABSORBER.

APPLICATION FILED JUNE 7, 1911.

Patented Jan. 26, 1915.

lll/VENTOR WTNESSES L Mja/mnag.

UNITED STATES onirica SHOCK-ABSORBER.

Maaate.

Specification of Letters Patent.

Application lel J une 7, 1911. Serial No. 631,719. Y

To all whom lit may concern.'

Be it known that I, ALVA W. BLANCHARD,

a citizen of the United States, residing in the borough of Brooklyn, in the county of Kings and State of NewYork, have invented certain new and useful Improvements Shock-Absorbers, of which the following 1s a speciication, reference being had therein to the accompanying drawings, forming part thereof.

My invention relates generally to shockabsorbers for vehicles and more particularly to shock-absorbers of the hydraulic type.

Among the objects of my invention are extreme simplicity of construction, inexpensiveness of manufacture and maintenance, a high degree of effectiveness of operation, non-liability to derangement, accessibility of parts, obviation of the possibility of violent contact of relatively movable parts, and obvi'ation of rattling.

More particular objects andadvantages of mv invention will hereinafter appear.

invention includes a liquid-containing cylinder which is closed to the atmosphere vat one side of a piston and open to the atmosphere at the' other side of the piston,

there being restricted liquid-conveying com- Y munication from one side of the piston to the other in all positions of piston movement. Moreparticularly, such communication is of constant extent for each direction of movementv of the piston and the movements of the'piston in one direction, for eX- lample, towardthe closed end of the cylinder are opposedby a comparatively slight resistance, but the movements of the piston in the opposite direction or away from the closed end of the cylinder are opposed by a comparatively great resistance, this latter res1stance, however, being entirely `due tou -the pressure of the outer air or atmosphere. In this connectlon as a means for causlng the difference in resistance, my invention includes a check-valve of appropriate and novel construction.

My invention also includes such a liquidcontaining cylinder closed at one end and in which is a hollow piston having an inner head, there being free com-munlcation from v the interior of the piston to the atmosphere and restricted communication from the. in-

. terior of the piston to the inside of the cylinder inward from the piston head at all points of piston movement. 1 r.

My invention also includes a hollow pls- Y inosphere,

ton having inner and outer heads and having an opening to the atmosphere spaced downward from the outer head in position to be covered by the cylinder so that the air contained in the piston will act as a cushion to prevent contact of the piston and the cylinder head.

In a hollow liquid-receiving piston open to or freely communicating with the atmy invention also includes splash fenders to prevent the splashing out of the liquid through the opening to the atmosphere.

In carrying out my invention, l provide springs reactive between the piston and its Patented Jan. 26, 31915..

support and between the cylinder and its as will appear from the following description.

I shall now describe the shock-absorber i embodying my invention illustrated in the accompanying drawings and shall thereafter point out my inventionin claims.

Figure l is an elevation partly broken away showing the shock-absorber in place on the chassis of an automobile. Fig..2 is an enlarged central vertical` section of the shock-absorber and its attaching brackets. Fig. 3 is a horizontal section on al plane indicated bythe line 3 3 of Fig. 2v as viewed from above. Fig. 4; is a similar view on a plane indicated by the line 4% yof Fig. 2. Fig. 5 is a further enlarged plan of the valve vbushing and valve carried thereby.

ig. 6 is an inverted plan vof the same.

ln the shock-absorber illustrated in the drawings, a vertically disposed cylinder il vis closed at its lower end and is completely open at its upper end. Within this cylinder ll. is a hollow piston l2 provided asshown with both inner or lower and outer or upper piston heads. rlhe piston 12 telescopes into iOO tlie upper open end of the cylinder ll and in the drawings the pisabopt a middle position tion from the interior of the piston to the atmosphere above the maximum level of the shock-absorbing liquid. The cylinder 11 is nearly filled with liquid, as indicated in Fig. 2, such as a lubricating oil, and the lower piston head has therein an upwardly opening check-valve for controlling the flow of liquid from the cylinder 11 to the interior of the hollow piston 12 and vice versa.

A slightly flanged valve bushing 14 screws upward through the lower piston head. The valve bushing 14 is cup-shaped, having upon its upper side a circular recess 15 outwardly from which or at the top of the bushing is formed a valve seat. A valveguiding post 16 projects upward from the center of the valve bushing, such post being shown as an ordinary small bolt screwed into the valve bushing and the head of which forms a valve-limiting abutment. A valve disk 17 is slidable and freely rotatable upon the post 15. Liquid-conveying openings 18 are provided through the valve bushing 14, these openings connecting the recess l5 with the cylinder below the piston and being shown as six in number arranged in a circular series. The valve disk 17 has therein two small liquid-conveying openings 19 which when the valve disk is upon its seat (Fig. 2) form the only communication between the recess 15 and the interior of the piston 12.

It is to be noted here that the circular recess 15 is a liquid-conveying channel providing communication between the openings 18 in the valve bushing and the openings 19 in the valve disk without regard to the rotation of the valve disk 17, which is thus permitted to freely assume any rotational position. The total cross-sectional area of the Iopenings ,19 in the valvedisk 17 is much less than the corresponding total area of the openings 18 in the valve bushing 14. As the piston 12 moves into the cylinder 11 the valve disk 17 will lift and the liquid in the cylinder below the piston will liow into the piston, the large number of large 'openings 18 in the valve bushing offering a comparatively slight resistance to the movement of the liquid into the hollow piston. However, when the piston 12 moves upwardly in the i cylinder 11 the valve disk 17 will seat upon the bushing 14 and liquid can only pass out of the piston and into the cylinder below the piston through the two small openings 19 in the valve disk 17 Therefore, a comparatively slight resistance is offered to the downward movement of the 'piston or' the upward movement of the cylinder and a comparatively great resistance is offered to the upward movement of the piston or the downward movement of the cylinder.

Air is freely admitted above the lower piston head and above the liquid in the piston, through the openings 13 near the upper end of the piston; and it is to be noted that 'valve disk 17 when a separating movement between the piston and cylinder takes place. l

That is to say, the resistance to separation of the piston and cylinder, or to movement of the piston away fromthe closed end of the cylinder, is provided solely by the barometric pressure of the outer air or atmosphere.

The openings 13 from the piston to the atmosphere are so located that they will be closed by the wall of the cylinder before the plston reaches the bottom of the cylinder so that the air will be trapped in the piston as the end of the stroke is approached and will actl as a cushion to prevent violent contact of the piston with the bottom of the cylinder.

The cylinder 11 is carried by the axle and the piston 12 is carried by the frame forming a part of the vehicle body. F or attaching purposes, the head of the cylinder 11 is centrally provided with a screw-threaded stem 20 and the upper or outer head of the piston 12 1s similarly provided with a similar stem 21. An L-shaped cylinder-supporting bracket 22 is secured to the vehicle aXle by a U-bolt 23 acting as a clamp (F ig. 1), and a horizontally proj ecting piston supporting bracket 24 has a base flange secured to the side member of the vehicle frame. The cyllnder stem 20 extends downward and passes loosely through a tapered stem-receiving opening of somewhat larger diameter than the stem in the horizontal arm of the cylinder-supporting bracket near its end. A nut 25 screws on the cylinder stem 20 below the bracket arm and has its upper face spherically rounded to fit into a complementary socket formed in the lower face of the bracket arm, thereby providing for limited pivotal movement in all directions. A stitl curved leaf spring 2G, shown as a four pronged star spring, through a central hole 1n which the cylinder stein 20 passes,` presses at its central part upon the upper surface of the bracket arm and presses at its end parts against the head of the cylinder ll,- th1s spring keeping the joint tight, taking up wear and preventing rattling. The piston stem 21 passes loosely through a somewhat larger tapered aperture in the horizontally projecting piston-supporting bracket- 24 and 1s provided'above the bracket with a nut 27,'which is spherically rounded onits lower side to pivotally fit into a complementary socket in the upper face of the bracket.

A stiff curved leaf spring 28 of star shape surrounds the piston stem 21. between the piston supporting bracket 24 and the upper piston head, at its center pressing upwardly against the bracket and at its ends 'pressing downward on the upper piston head. The construction and function of the spring 28 above the piston are similar to the construction and function of the spring 26 below the cylinder. The .resistance tothe downward movement of the piston 12 or to the upward movement of the cylinder 11 being, as hereinbefore explained, comparatively slight, the springs 26 and 28 are strong enough to transmit this movement from the supporting brackets 22 and 24 without yielding, as any yielding would cause rattling.

A thin sheet metal shell 29 is carried by the piston l2 and extends down over the upper open end of the cylinder 11, covering the upper end of the piston 12, protecting it and the cylinder from dust and grit, and also concealing the piston from view and giving a good finish. The shell 29 is spaced a substantial distance from the wall of the cylinder 11, longitudinal guide ribs 30 shown as four in number (Fig. 4.), being provided on the outer surface of the cylinder against which the shell 29 fits suificiently tight to prevent rattling. Perfectly free .access of 'air entering and leaving the hollow piston 12is had between these ribs 30. The shell 29 is closed at its top and extends over the upper piston head l beneath the curved leaf spring 28 by which it is held in place.I

In the operation of the device the liquid i within the piston 12 is necessarily somewhat agitated, and to guard against its loss by splashing out through the openings 13 near the upper end of the piston, I provide splash fenders 31 at the upper part of the inside of the piston. These splash fenders are inwardly and downwardly extending plates or walls formed integral with the cylindrlcal side wall of the piston and extending more than half way across the interior piston space alternately in overlapping relation from opposite sides, four such fenders being shown, two at each side (Figs. 2 and 4). Urdinary lubricating oil may be used as the shock absorbing liquid and should a little of it be lost it may be replenished from time to time l `through an oil supply opening in the upper piston head, this opening being closed by an ordinary screw-plug 32.

j The details of operation have been described along with the description of the construction, but the general operation of the device considered as a whole requires some further explanation. rThe cylinder 11 being carried by the axle of the vehicle and the piston 12 being carried by the vehicle frame, it is to be noted that the downward movement of the frame or lthe upward movement of the axle will meet with comparatively slight resistance, whereas the upward movement of the vehicle frame or the downward movement of the axle, these being the movements due tothe recoil of the vehicle and under ordinary working these openings i 13 are uncovered. It should be noted that the barometric or atmospheric pressure constitutes the maximum resistance to which the piston 12 is subjected in its upward or outward movement in the cylinder 11. With a very strong vehicle spring the recoil might in some cases be sufiicient to overcome the atmospheric pressure and produce a vacuum in the cylinder below the piston.

This condition could only occurfollowing f an extreme position of movement togethei` of the piston and cylinder and could only endure while the vehicle spring was under greatest tension, so that under no possibility could there be a rebound effect at the limit of the separating movement. Moreover, the possibility of the production of such a vacuum is directly dependent upon the cross-sectional area of the piston and if desired this can be made large enough to preclude the possibility of a vacuum ever being formed therein. I have found in practice that with a piston diameter of three inches excellent results are obtained. In case of the production of a vacuum, as above mentioned, the level of the shock-absorbing liquid may rise above the open upper end of the cylinder 11, but obviously none of this liquid could be lost by overflow, as all of the liquid raised would be contained within the hollow piston 12.

Among the great advantages of the open top cylinder and the hollow piston freely communicating with the atmosphere, are the avoidance of the necessity of any packing.

No joint has to be tight except the long sliding contact of the piston and cylinder, and the abundance of lubricating oil assures both tightness and eective lubrication at this joint. Another great advantage is the ease with which the device may be supplied with oil and the supply replenished as well as that no special kind of oil is required.

While there is nothing about the device liable to get out of order, tol give way or soon wear out, yet it .is to be noted that all parts are readily accessible for inspection and renewal. For example, by merely disconnecting either the piston or the cylinder from the vehicle, access is had to the check valve which may be removed n 250250 merely by unscrewing the valve bushing 14.. All other parts are even more readily accessible. It is obvious that various modifications may be made in the construction shown in -the drawings and above particularly described within the principle and scope of my invention.

I claim: p

1. A shock-absorber comprising a liquidcontaining cylinder, and a piston movable longitudinally in the cylinder, the cylinder being closed to the atmosphere at one side of the piston and being freely open to the atmosphere at the other side of the piston so as to subject the liquid in the cylinder to atmospheric pressure only at one side only of the piston, such atmospheric pressure being the maximum resistance to the movement of the piston in one direction in the cylinder, freely open restricted communication for the liquid being provided from one side to the other of the piston in all positions of the piston in the cylinder and means being'A provided to prevent the liquid overiiowing from the open side of the cylinder should the piston move with suiiicient force to overcome the pressure of the atmosphere.

2. A shock-absorber comprising a liquidcontaining cylinder, a piston movable longitudinally in the cylinder, the cylinder being closed to the atmosphere at one side of the piston and being freely open to the atmosphere at the other side of the piston, atmospheric pressure constituting the maximum resistance to the movement of the piston away from the closed and toward the open side of the cylinder, and a check-valve controlling the liquid and arranged to resist the movement of the piston in the cylinder with' a comparatively great resistance in one direction of relative movement of the piston in the cylinder and with a comparatively slight resistance in the other direction of relative movement of the piston in the cylinder and means being provided to prevent the Aliquid overflowing from the open side of the cylinder should the piston move with sufhciennforce to overcome the pressure of the atmosphere.

3. A shock-absorber comprising a liquidcontaining cylinder, a piston movable longitudinally in the cylinder, the cylinder being closed to the atmosphere at one side of the piston and being 'freely open to the atmosphere at the other side of the piston, atmospheric pressure constituting the maximum resistance to the movement of the piston away from the closed and toward the open side of the cylinder, and a liquid-controlling check-valve arranged to offer a comparatively slight resistance to the movement of the liquid past the piston from the closed side to the open side of the cylinder and to offer a comparatively great resistance to the movement of the liquid in the opposite di` rection'and means being provided to prevent the liquid overflowing from the open 'side of the cylinder when the piston moves against the comparatively great resistance as controlled and limited by the pressure of the atmosphere.

4. A shock-absorber comprising a liquidcontaining cylinder, and a piston movable longitudinally in the cylinder, the cylinder being closed to the atmosphere at one side of the piston and being freely open to the atmosphere at the other side of the piston so as to subject the liquid in the cylinder to atmospheric pressure only at one side only of the piston such atmospheric pressure being the maximum resistance to the movement of the piston in one direction in the cylinder, freely open restricted communication of constant extent for each direction of piston movement being provided for the liquid from one side to the other of the piston in all positions of the piston in the cylinder and means being provided to prevent the liquid overiiowing from the open side of the cylinder should the piston move with suiiicient force to overcome the pressure of the atmosphere.

5. In combination with a vehicle body and its axle, and a spring between them; a shock-absorber comprising a substantially vertical liquid-containing cylinder carried bythe axle and open at the top, and in the cylinder a hollow liquid-receiving .piston having a closed upper head and a lower head having therein a restricted opening, the upper part of the piston beng'rnovable above 'the cylinder wall and the piston having an 6. In combination with a vehicle bodyl and its axle, and a spring between them; a shock-absorber comprising a substantially vertical liquid-containing cylinder carried by the axle and open at the top, a hollow liquid-receiving piston in the cylinder having a restricted communication to the interior of the cylinder and having a closed upper end, the upperend of the piston being movable above the wall of the cylinder and the piston having an opening from its interior to the atmosphere in position to be covered by the wall of the cylinder before the piston reaches its, lowermost position therein, and an outer shell carried by the upper end of the piston and extending downward over the piston opening and over the upper end of the cylinder in spaced relation to the piston and the cylinder to provide for free access of air to the interior of the piston, the cylinder being provided with spaced longitudinal guides for the outer shell.

7. A shock-absorber comprising a substantially vertical liquidcontaining cylinmemes;

- the cylinder and having an opening at its upper .part providing free communication with the atmosphere, the inside of the piston being provided at the upper part with downwardly inclined alternately overlapping splash fenders. v

9. A shock-absorber comprising a substantially vertical liquid-containing cylinder open at the top:l and inthe cylinder a hollow liquid-receiving piston having a lower head, the upper portion of the piston being movable above the top of the cylinder wall and having an opening to the atmosphere above the maximum liquid level to subject the liquid in the cylinder and pist0n to atmospheric pressure only at the upper side of the piston, such atmospheric pressure being the maximum resistance to which the piston is subjected in its upward movement in the cylinder, the lowerend of the cylinder being closed to the atmosphere, freely open restricted communication for the liquid being provided between the interior ofthe hollow piston and the interior of the cylinder below the piston in all positions of the piston in the cylinder.

10. A shock-absorber comprising av substantially vertical liquid-containing cylind er open at the top, in the cylinder a hollow the upper portion of the piston^being movable above the top of the cylinder wall and having an opening to the atmosphere above the maximum liquid leveLto subject the liquid in thel cylinder and piston "to atmospheric pressure only at the upper side of the pistq'n, such atmospheric pressure being the maximumv resistance to which the piston is subjected in its upward movement in the l ylinder, the lower end of the cylinder bemg closed to the atmosphere, and a checkvalye controlling the liquid and arranged to resist the movement of the piston in the cylinder with acomparatively great resistance lquid-receiving piston having a lower head,

in one direction of relative movement of the piston in the cylinder and with a comparatively slight resistance in the other direction of relative movement of the piston in the cylinder.

11. A shock-absorber comprising a substantially vertical liquid-containing cylinder open at the top, in the cylinder a hollow liquid-receiving piston having a lower head,

the upper portion of the piston being movable above the top of the cylinder wall and having an opening to the atmosphere above the maximum liquid level to subject the liq- .uid in the cylinder and piston to atmosplieric pressure only at the upper side of the piston, such atmospheric pressure being vthe maximum resistance towhich the piston is subjected in its'upward vmovement in the cylinder, the lower end of the cylinder being closed to the atmosphere, and a liquidcontrollingcheck-valve arranged to offer a comparatively slight resistance to the movement of the liquid from the cylinder below the piston into the hollow piston and to cooperate withI atmospheric pressure to o'er a comparatively great resistance to the movement of the liquid in the opposite direction.

12. A shock-absorber comprising a substantially vertical liquid-containing cylinder open at the top, and in the cylinder a hollow liquid-receiving piston having a lower head, the upper portion of the piston being movable above the top of the cylinder wall and having an opening to the atmosphere above the maximum liquid level to subject the liquid in the cylinder and piston to atmospheric pressure only at the upper side of the piston, such atmospheric pressure being the maximum resistance to which the piston is subjected in its upward movement in the cylinder, the'lower end of the cylinder being closed to the atmosphere, freely fopen restricted communication of constant 

